panel innerHTML not showing

I have a TabPanel which gets a panel added during run. The panel has it's contents replaced using an Ext.Template - or at least, that's what should happen.

Using firebug I set a breakpoint before the panel gets added to the TabPanel and I see the panel has an innerHTML element with the required text. However, it goes to screen and nadda.

Code:

// User is already configured and known good
// tbPnl is the preconfigured TabPanel
var adPnl = new Ext.Panel({
id: 'adPnl',
title: 'user',
autoHeight: true,
autoWidth: true});
var adTpl = new Ext.Template(
'<p>name: {name}</p>',
'<p>something: {something}</p>');
adTpl.overwrite(adPnl, User);
//adTpl.overwrite(adPnl.body, User); //doesn't work.
tbPnl.add(adPnl);
// at this point I see innerHTML on adPnl with my values filled out
tbPnl.setActiveTab(adPnl);
// the tab appears with the header but no data. Not in the panel and not in the rendered HTML